This invention is generally concerned with a mailing machine including a pulse width modulated signal circuit for controlling a load, and more particularly with a mailing machine base including a multiple channel, pulse width modulated, signal circuit for controlling a plurality of electrical loads.
As shown in U.S. Pat. No. 5,217,551 for a Mailing Machine Including a Process For Selectively Moistening Envelopes Fed Thereto, by John R. Nobile, et. al and assigned to the assignee of the present invention, there is disclosed a mailing machine including a microprocessor which is programmed for controlling separate motors for driving sheet feeding and postage printing structures, and which is programmed for controlling a solenoid for moving a baffle between one position wherein respective sheets are guided thereby into engagement with flap deflecting structure and another position wherein the respective sheets are guided thereby out of engagement with the flap deflecting structure. In such microprocessor applications the microprocessor includes a plurality of timers which are utilized for producing pulse width modulated signals to drive separate power amplifiers connected between the microprocessor and solenoid and each of the motors. Such microprocessor controlled systems are relatively costly to implement due to the high cost of microprocessors which have sufficient capacity to set up multiple timers for controlling multiple pulse width modulated load driving channels. Accordingly:
an object of the invention is to provide an improved mailing machine;
another object is to provide a low cost circuit for driving multiple electrical loads in a mailing machine base;
another object is to provide a multiple channel, pulse width modulated signal control circuit for controlling a plurality of electrical loads; and
another object is to provide an inexpensive arrangement of apparatus for implementing pulse width modulated signal control of a plurality of electrical loads, including a solenoid and multiple motors.